Open Data supplied by Natural Environment Research Council (NERC)

Bissett-Bermann 9040 Conductivity Temperature and Depth

The basic configuration of the B-B 9040 CTD incorporates pressure, temperature and conductivity sensors which could be logged digitally. This system also made it possible to derive other parameters, such as salinity, depth and sound velocity.

The instrument was versatile and it was possible to attach a dissolved oxygen sensor or to change the CTD housing, allowing it to obtain data from deeper layers in the water column. The accuracy for salinity is ±0.02 ppt , and ±0.02°C for temperature.

Caution

Some of the salinity data collected on this cruise are noisy (±0.01 psu)

Data Processing

The raw data were previously manually edited, resequenced and archived in 2 files. One file contained temperature, salinity and depth frequencies with time elapsed and the other contained decca positional infomation.

These data were reprocessed in Febuary 2001.

Calibrations

The following constants (obtained from printouts of the data) were used to convert to real units and calibrate.

Temperature Constant

2128.0

Salinity Constant

4999.4

Depth Constant

9735.5

The downcasts had a temperature correction applied to lessen salinity spiking.